Internal-combustion engines – Accessories – Covers – trays – vibrators – corrosion inhibitors – air filters
Reexamination Certificate
2000-03-30
2001-04-17
Kamen, Noah P. (Department: 3747)
Internal-combustion engines
Accessories
Covers, trays, vibrators, corrosion inhibitors, air filters
C055SDIG002
Reexamination Certificate
active
06216661
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to devices for cleaning and filtering materials, and more specifically to a relatively small, removable, temporary carburetor cover for short term installation on a carburetor. The present cover includes filtering means therein, so the engine may be run for carburetor tuning and adjustment purposes with the cover in place, to prevent the ingestion of foreign matter (dirt, small parts, etc.).
2. Description of the Related Art
While nearly all motor vehicles used in street operation are equipped with fuel injection systems for better exhaust emissions control, better flexibility under various conditions (cold starting, better fuel distribution, etc.), there are many classes of off-road motor vehicles which still use carburetors, due to the rules governing those various classes.
This is particularly true of motor vehicles used in racing (i.e., race cars of various types), ranging from so-called “hobby stocks” up to racing automobiles used in major league Winston Cup racing. Most racing classes for full-bodied cars, as well as certain classes of open wheel cars which run in various minor league series, are required to use carburetors for their fuel distribution systems, rather than fuel injection.
Air intake filter systems for motor vehicle carburetors are typically secured directly to the mouth of the carburetor, with no intervening intake system. Such filters are generally relatively large in comparison to the carburetor diameter, in order to provide a relatively large filter area to produce a relatively low restriction for air passing through the filter and its housing. Accordingly, the typical filter housings of such carburetors extend well beyond the lateral dimensions of the carburetor.
This is ordinarily not a serious problem, as access to the carburetor is obviously not required while the vehicle is in motion. However, access to the carburetor is required when the engine is being tuned or adjusted, for adjusting fuel/air mixtures, adjusting the point at which the secondary throttles begin to open in multiple barrel carburetors, etc. Many such adjustments may be accomplished while the engine is running, and in fact, it can be quite difficult to accurately accomplish many such adjustments when the engine is shut down. Yet, the conventional air cleaner must be removed from the carburetor for access to the various adjustment points.
This may not be a significant problem under some circumstances, but the removal of the air cleaner from a carburetor while the engine is running in a relatively dirty environment can lead to the ingestion of dirt and other foreign matter into the engine, which is always harmful to the engine and may be disastrous. This is particularly true in many automobile racing environments, particularly on dirt tracks and even at a paved track with a dirt or turf infield area where the cars are being worked on before or between races. The amount of dirt and dust which is kicked up into the air by a number of racing automobiles in such an environment is considerable, and in fact often reaches an extent to which the dust and dirt is quite visible in the air at such tracks during racing events. As an operating engine performs as a pump, drawing air from the atmosphere through the carburetor and into the engine, it will be seen that a considerable amount of dirt and dust may enter a carburetor and engine during the time the engine is running in relatively dirty air.
In addition to the above considerations, racing mechanics are always pressed for time, and it is quite easy under such circumstances to inadvertently drop a small part which may fall into the carburetor throat and thence be ingested into the engine, where it almost always causes considerable damage. Even if the mechanic realizes such a part has been dropped into the carburetor throat, there may be insufficient time to shut down the engine before the part passes into one of the cylinders and causes internal damage to the engine.
Even if the engine is not operating when such foreign matter is dropped into the carburetor, often the engine intake system must be disassembled for recovery of the part. Such disassembly obviously requires additional time, which is seldom available at a race. Accordingly, almost all mechanics will cover the carburetor throat when the air cleaner is removed, in order to preclude the entry of dust and dirt therein and the dropping of any foreign objects into the carburetor throat when the engine is not running.
However, such cover plates do not allow the passage of any air therethrough, and thus cannot be used when the engine is running. The only solution is to keep the conventional, relatively large air cleaner in place, or to remove it for adjustments to the carburetor and hope that no significant amount of dust, dirt, or foreign matter passes through the carburetor during the time the air cleaner is removed.
Accordingly, a need will be seen for a filtered carburetor cover which may be temporarily installed on a carburetor throat when the conventional air cleaner or screen is removed. The present carburetor cover is relatively small and has a diameter substantially the same as, or at least no larger than, the carburetor with which it is used, in order to provide access to the external components of the carburetor for adjusting and tuning while the engine is running. The present carburetor cover includes filter elements in the intake portion thereof, to preclude the ingestion of any significant amount of foreign matter into the engine while it is running.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 2,761,527 issued on Sep. 4, 1956 to John J. Dreznes, titled “Filter Body,” describes a relatively large and bulky air filter, resembling the conventional oil bath filter used commonly up to the 1960s. the Dreznes filter includes a fitting for installing over the throat of a carburetor, with the fitting being defined by a clamping ring 41 therearound. The clamping ring has a considerably smaller diameter than the body or housing of the air cleaner, as may be readily seen in FIG. 3 of the drawings of the Dreznes Patent. Accordingly, the sides of a carburetor over which the Dreznes air cleaner is installed, cannot be readily accessed. The present filtered carburetor cover is not intended for use during normal engine operation, but as the name indicates, is a cover with a filter therein for use in tuning and adjustment operations and which provides full access to the external components of the carburetor.
U.S. Pat. No. 5,307,771 issued on May 3, 1994 to Alwin J. Stahel II et al., titled “Motorcycle Air Cleaner,” describes an air cleaner assembly having a secondary throttle assembly on one side thereof. The assembly is operated by manifold vacuum from the engine, and is set to open when manifold pressure increases, i.e., when the throttle is opened for increased engine power. This provides a larger intake area to the air filter, thus producing less restriction to the filter for better engine “breathing.” As noted further above, this is the reason that conventional air cleaners are relatively large in comparison to the carburetor diameter, i.e., to provide a significantly larger cross sectional area for the air cleaner element in order to compensate at least partially for the restriction of the air cleaner element. The Stahel II et al. air cleaner body extends well beyond the outer dimensions of the carburetor, as can be seen in the cross section of FIG. 2A of the Stahel II et al. Patent. In contrast, the present filtered carburetor cover preferably extends no further than the outer dimensions of the carburetor, in order to allow complete access to the carburetor as required when the filter cover is installed thereon.
U.S. Pat. No. 5,368,621 issued on Nov. 29, 1994 to Stephen R. Pool, titled “Filtering Air Cleaner Cover For Internal Combustion Engine,” describes a conventio
Dinges Robert J.
Pickens Randy
Kamen Noah P.
Litman Richard C.
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